U.S. patent number 5,069,691 [Application Number 07/613,212] was granted by the patent office on 1991-12-03 for portable filtration unit.
This patent grant is currently assigned to Abatement Technologies. Invention is credited to Blair Harber, Jr., Gary Kruse, David Shagott, Daniel Sutherland, Terrell Travis.
United States Patent |
5,069,691 |
Travis , et al. |
December 3, 1991 |
**Please see images for:
( Certificate of Correction ) ( Reexamination Certificate
) ** |
Portable filtration unit
Abstract
A portable vacuum and air filtration unit, comprising: a
plurality of separately transportable modules and a means for
locking the modules together during use, an air inlet located in
one of the modules, a debris screen and a means for receiving
debris stopped by the screen located in one of the modules, an
electrostatic filter located in one of the modules, a bag filter
assembly located in one of the modules, a HEPA filter assembly
located in one of the modules, and a means for drawing a
substantial volume of air through the inlet, screen, electrostatic
filter, bag filter assembly and HEPA filter assembly.
Inventors: |
Travis; Terrell (Alpharetta,
GA), Shagott; David (Duluth, GA), Kruse; Gary
(Lincoln University, PA), Sutherland; Daniel (Ontario,
CA), Harber, Jr.; Blair (Ontario, CA) |
Assignee: |
Abatement Technologies (Duluth,
GA)
|
Family
ID: |
24456341 |
Appl.
No.: |
07/613,212 |
Filed: |
November 14, 1990 |
Current U.S.
Class: |
96/57; 55/350.1;
15/304; 15/352; 55/356; 55/482; 55/467; 55/484 |
Current CPC
Class: |
A47L
5/38 (20130101) |
Current International
Class: |
A47L
5/38 (20060101); A47L 5/38 (20060101); A47L
5/38 (20060101); A47L 5/22 (20060101); A47L
5/22 (20060101); A47L 5/22 (20060101); B01D
050/00 () |
Field of
Search: |
;55/482,484,316,124,126,356,387,320,323,324,342,467,350 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Aqualine Resources, Inc. "Master Vac" Brochure, Nov. 1990. .
Health Aire Company, Inc. PV4000 Brochure, Oct. 25, 1990. .
Vac Systems Industries Advertisement and Brochure, Oct. 1990. .
Pringle Co. "Power-Vac" Brochures, Jul. 1990. .
Brochure for U.S. Industrial Company's OMNI/HVAC Duct Cleaning
System, Feb. 1991. .
Jan. 1991 Advertisement and Brochure for "Vent Vac" Duct Vacuum.
.
Jan. 1991 Advertisement and Brochure for "Mechaniclean" Duct
Cleaner System..
|
Primary Examiner: Nozick; Bernard
Attorney, Agent or Firm: Kilpatrick & Cody
Claims
We claim:
1. A portable vacuum and air filtration unit, comprising:
a) a plurality of separately transportable modules and a means for
locking the modules together during use;
b) an air inlet located in one of the modules;
c) a debris deflector and a means for receiving debris stopped by
the deflector located in one of the modules;
d) an electrostatic filter located in one of the modules;
e) a bag filter assembly located in one of the modules;
f) a HEPA filter assembly located in one of the modules; and
g) a means for drawing a substantial volume of air through the
inlet, deflector, electrostatic filter, bag filter assembly and
HEPA filter assembly.
2. A portable vacuum and air filtration unit, comprising a
plurality of separately transportable modules and a means for
locking the modules together during use into a rigidly
interconnected chest containing an inlet, a debris deflector, a
means for receiving debris stopped by the deflector, an
electrostatic filter, a bag filter assembly, a HEPA filter
assembly, and a means for drawing air through the inlet, deflector,
electrostatic filter, bag filter and HEPA filter.
Description
BACKGROUND OF THE INVENTION
The present invention relates to portable filtration units for
cleaning heating, ventilation, and air conditioning ("HVAC")
ductwork in residential and commercial buildings. Such cleaning is
often needed, particularly in older buildings, to remove
accumulations of dust, dirt, and other debris that collect in the
ductwork and can cause allergic reactions or pose other health and
safety risks.
Generally, HVAC duct cleaning has been accomplished using large,
truck-mounted vacuum units. These vacuum units are driven by a
power takeoff from the truck engine and typically generate air flow
of 10,000 to 20,000 cubic feet per minute ("CFM") at the truck. Of
course, the truck must normally be parked outside a convenient
doorway into the building, and the building ductwork is connected
to the truck mounted vacuum unit by a long, flexible, temporary
duct or hose. Because of losses in the flexible duct, the airflow
generated at the input end of the flexible duct typically drops
significantly to around 5000 to 8000 CFM or less.
In use, once the vacuum unit is connected to the building ductwork,
a wand or "skipper" is inserted into and passed through the
building ductwork. The skipper is connected to an air compressor
and has a head with multiple air jets. Compressed air forced
through the skipper air jets and directed toward the vacuum unit
loosens, agitates and suspends in the air dirt and dust in the
ductwork and blows other debris toward the vacuum unit. The suction
generated by the vacuum unit pulls the suspended dirt, dust and
debris into the truck and blows it through cloth bag filters, which
typically trap only 40% to 60% of the dirt and dust before the
remainder is exhausted with the air into the atmosphere. Cleaning
all the ducts in the building can take 2 to 3 hours in a typical
residence and longer in a commercial building.
There are several disadvantages associated with truck-mounted
vacuum filtration units. First, such units are expensive to
purchase and to operate. For example, truck mounted units require a
two person crew to use. Further, because of the length of the
temporary duct, truck mounted units require 1 to 2 hours to set up.
Therefore, a typical crew can only clean two buildings in one day.
In addition, because the vacuum unit is powered by the truck's
engine, the truck must be left running during the entire cleaning
operation, not only using a large quantity of gasoline or diesel
fuel which the vacuum unit operator must supply, but also
increasing the maintenance requirements of the truck. Finally, from
the building owner's perspective, truck mounted units are
exhausting 5000 to 8000 CFM of air conditioned or heated air into
the atmosphere for 2 to 3 hours, which can have a large impact on
the owner's utility bill.
A more important disadvantage with truck mounted vacuum units is
the dust and dirt the units exhaust. With filters that are at best
40% to 60% efficient, truck-mounted vacuum units spew out large
amounts of dust or dirt, most of which settles back on the building
being cleaned. The filters used on these truck-mounted units are
particularly ineffective (less than 10% efficient) at filtering the
small, invisible particles of 10 microns or less in diameter that
are often the most harmful to humans. When this dust or dirt also
contains asbestos fibers (a not unusual occurrence in older
buildings), or worse--pathogens like legionella or other disease
causing materials--the filth sprayed about by truck mounted vacuum
units can be a health risk, particularly for the operator, if not
an environmental hazard.
A third disadvantage to truck mounted units is that the unit must
remain outside the building, and because of losses in the flexible
duct, the duct can be of only limited length. Thus, although usable
for residential and low rise commercial buildings, truck mounted
vacuum units cannot be used on buildings more that a few stories
tall.
Finally, truck mounted vacuum units are noisy. Although the noise
generated by these units may not be intrusive in an busy urban
setting, the deafening roar and whine generated by truck mounted
units can be intolerable on the quiet suburban residential streets
where the units are typically employed.
Some of the described problems are answered by prior art portable
filtration units. Currently, there are several vacuum filtration
units on the market that are intended to be portable. Some of these
units are operated by a gasoline engine and have many of the
drawback discussed above, such as noise, expense, and the
requirement of operation outside the building. There are prior
portable units that are operated by electric motors; however, until
the present invention, none of these units have been entirely
satisfactory.
For example, one such unit is powered by a 3 horsepower electric
motor and weighs less than 200 pounds. However, the electric motor
of this unit requires 230 volt electric service and draws 18
amperes. Many residential or light commercial building contain no
provision for 230 volt electric service in the locations where the
vacuum unit must be operated. Furthermore, the airflow generated by
this unit is less than 2000 CFM, which is insufficient to
thoroughly clean HVAC ductwork. Finally, most important, this unit
also uses inefficient cloth filtration bags, which results in most
of the dust and dirt collected by the unit being exhausted back
into the building being cleaned or adjoining buildings.
A second electric unit currently on the market is powered by two 5
horsepower 208/230 volt electric motors, which are also unsuitable
for residential and light commercial buildings. Furthermore, the
unit has two parts; one weighs 150 pounds, and the other weighs 350
pounds. The weight of this unit reduces its portability and
requires a two person crew. This unit does generate an airflow of
4000 to 5000 CFM and the filtering system includes a high
efficiency particulate air ("HEPA") filter.
A third unit currently on the market includes a HEPA filter, runs
on 110 volts, and is of a modular design. However, the electric
motors on this unit draw 70 amperes, and render the unit virtually
unusable in residential or light commercial buildings where the
typical electric circuit is 15 amperes.
SUMMARY OF THE INVENTION
The present invention solves the problems of the prior art in a
portable filtration unit that contains four separate, easily
maintained filters; a large particle filter, a cleanable and
reusable electrostatic filter, a bag filter, and a HEPA filter.
This cascade of filters exhausts almost totally clean air while
successfully dealing with the astoundingly wide range of debris
found in HVAC ductwork. The unit is powered by multiple 110 volt
electric motors, each drawing less than 15 amperes. The blowers
attached to the electric motors generate a total airflow of at
least 4000 CFM. The filtration unit is of wheel-mounted, modular
design, with the motors, blowers and filters housed in separate,
easily connected compartments. The unit is easily transported to
the HVAC system to be cleaned and can be quickly set up by a single
person.
Accordingly, one objective of the present invention is to provide
an inexpensive filtration unit.
Another objective of the present invention is to provide a portable
filtration unit.
A further objective of the present invention is to provide a
filtration unit that can be easily transported and set up by a
single person.
Still another objective of the present invention is to provide a
filtration unit which is suitable for use in high rise commercial
buildings.
Still another objective of the present invention is to provide a
filtration unit that operates on standard household electric
current.
A further objective of the present invention is to provide a
filtration unit which contains a HEPA filter.
Still another objective of the present invention is to provide a
filtration unit that is modular.
A further objective of the present invention is to provide a
filtration unit in which filter life is maximized and operating
costs minimized.
Still another objective of the present invention is to provide a
filtration unit which provides a deflector baffle which will
prevent objects drawn into the unit from being propelled through
the unit thereby damaging the filters.
These and other objectives and advantages of the present invention
will become apparent from the detailed description and claims which
follow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of one embodiment of the
present invention.
FIG. 2 is an elevation of the embodiment of the present invention
shown in FIG. 1.
FIG. 3 is a longitudinal cross section taken substantially through
the center of the unit shown in FIGS. 1 and 2.
FIG. 4 is an exploded perspective view of a second embodiment of
the present invention.
FIG. 5 is an elevation of the second embodiment of the present
invention of FIG. 4.
FIG. 6 is a longitudinal cross section taken substantially through
the center of the unit shown in FIGS. 4 and 5.
DETAILED DESCRIPTION OF THE DRAWINGS
As can be seen in FIGS. 1, 2, 3, 4, 5, and 6, the filtration unit
10 has several chest-like modules which are easily maneuvered using
carrying handles 84 and are connected for use by cam locks 12. The
first inlet module 14 and all other sheet components of unit 10,
except as otherwise noted, are preferably made of steel, stainless
steel, aluminum, or aluminum alloy. Inlet module 14 includes an air
inlet 16, which is preferably at a 45.degree. angle and to which
duct connector 18 is attached, rests on castors 17 which swivel
360.degree. and can be locked, and is moved using carrying handles
84. Duct connector 18 is preferably made of steel, stainless steel,
aluminum, or aluminum alloy, but other suitable materials may be
used. Duct connector 18 may be straight or angled (not shown) and
join a single duct inlet 16 as shown in FIG. 4 or, as shown in FIG.
1, may join multiple smaller ducts to inlet 16 for multiple vacuum
inlets.
Inlet module 14 also contains particulate deflector 20, a
perforated sturdy sheet positioned in the incoming airstream to
deflect large debris entering inlet module 14 through inlet 16 into
collection drawer 22. Drawer 22 is preferably made of steel,
stainless steel, aluminum, or aluminum alloy and as can be seen in
FIGS. 1 and 4, can be easily removed from inlet module 14 by
pulling on locking handle 24. As can be seen in FIGS. 1, 2, 4, and
5, the rear 26 of drawer 22 forms two V-shaped areas 25 and 27 that
trap particles, thereby allowing any particles entering drawer 2 to
precipitate to the bottom of drawer 22 and remain there despite the
turbulence above drawer 22 created by air entering inlet module 14
through inlet 16. Drawer 22 also contains a gasket 28 which in
combination with locking handle 24, seals drawer 22 against front
13 of inlet module 14. Deflector 20 in combination with drawer 22
minimizes premature loading on filter 30 and bag filter 38, thereby
maximizing filter life and airflow and reducing filter replacement
costs.
Air entering inlet module 14 passes from the large debris-trapping
chamber 11 through electrostatic prefilter 30. Electrostatic
filters of the type used in unit 10 are well-known in the art and
are available from companies like Air Purification of Houston.
Filter 30 is accessible through filter door 33. In the event filter
30 becomes clogged, as shown by a rise in pressure differential on
magnahelic gauge 32, access door 34 can be removed and filter 30
tapped or vibrated to loosen the dirt, dust, or other debris that
has accumulated on the upstream side 31 of filter 30. Access door
34 is then reinstalled on inlet module 14. As can be seen in FIGS.
3 and 5, the debris so loosened from filter 30 falls into drawer
22. The condition of filter 30 can also be monitored through
plexiglass window 15.
The screened and prefiltered air that has passed through filter 30
then enters bag filter module 36, which is of similar chest-like
construction and attaches to inlet module 14 by cam locks 12 and is
sealed by gasket 40. Bag filter module 36 contains fiberglass cloth
bag filters 38. Such filters 38 are well-known in the art and are
available, for instance, from Cambridge Filter Corporation. Air
passing into second module 36 flows through filters 38 and exits
bag filter module 36.
As can be seen in FIGS. 1, 2, and 3, in one embodiment of the
present invention, the screened and filtered air exiting bag filter
module 36 enters HEPA filter module 44, which is of like
construction to bag filter module 36, is attached to bag filter
module 36 by cam locks 12, and is sealed against bag filter module
36 by gasket 46. HEPA filter module 44 contains high efficiency
particulate air ("HEPA") filters 48, which filters are also
well-known in the art. Similar HEPA filters may be obtained from
Cambridge Filter Corporation. Air entering HEPA filter module 44
passes through HEPA filters 48, which filter out 99.97% of the dust
and dirt particles 0.3 microns or larger in size suspended in the
air, and enters fan modules 50 and 52.
Fan modules 50 and 52, which are of similar construction to inlet
module 14, bag filter module 36 and HEPA filter module 44, each
contain an electric motor 54, which drives a centrifugal fan blower
56. Fan modules 50 and 52, attach to each other and HEPA filter
module 44 by cam locks 12, and are sealed by gaskets 45 and 51.
Although the embodiment shown in FIGS. 1, 2, and 3 uses two motors
54 and two blowers 56, fewer or more motors 54 and blowers 56 can
be used in sizes and configurations dictated by the air handling
capacity desired. Each motor 54 should preferably run on standard
120 volt household current and draw no more than 15 amperes. A
sufficient number of pairs of motor 54 and blower 56 are used to
generate an airflow of at least 3500 CFM, with 4000 CFM to 6000 CFM
being preferred. Fan module 52 also contains control panel 62,
which controls both fan module 52 and fan module 50. Control panel
62 contains magnahelic gauge 64, which is used to monitor the
airflow resistance through the entire system as duct contaminates
load the filters and reduce airflow. Power loss alarms 66 sound if
power is interrupted to that circuit (thereby stopping motor 54 and
reducing the airflow below optimum). Amperage gauges 68 monitor the
current drawn by motors 54 and blowers 5 and allow the operator to
monitor each motor 54 and blower 56 pair individually, while power
indicators 70 allow the operator to visually determine which motors
54 are operating, even when the operator is not standing next to
the unit 10. For safety, circuit breakers 72 and power switches 76
are also provided. Hour meters 74 allow the unit owner to monitor
how long each motor 54 of unit 10 has been operated. Control panel
62 also contains ground fault interrupter outlets 78 for use by the
operator for accessory equipment and which also protects motors 54
from internal short circuits. Alarm bypasses 82 can be used to
disengage power loss alarms 66 when desired. Unit 10 is supplied
power through power connectors 80. Each motor 54 has its own power
connector 80, allowing each motor 54 of unit 10 to be connected to
separate 15 ampere electrical circuits. Fan modules 50 and 52 may
also contain an electric limit switch (not shown) which
automatically disengages power to motors 54 in the event either fan
modules 50 or 52 are disconnected from each other or HEPA filter
module 44. Virtually clean air entering fan modules 50 and 52 is
exhausted out a baffled exhaust port (not shown) located on the
side of fan modules 50 and 52 opposite control panels 62. The
exhaust port (not shown) also has a door (not shown) which prevents
air from entering the exhaust port in the event both motor 54 and
blower 56 pairs are not operated simultaneously.
A second embodiment of the present invention is shown in FIGS. 4, 5
and 6. In the second embodiment, screened and filtered air passing
through filters 38 and exiting bag filter module 36 enters fan/HEPA
module 60. Fan/HEPA module 60 contains HEPA filters 48, three pairs
of motors 54 and blowers 56, castors 17, carrying handles 84, and
control panel 62. Like fan modules 50 and 52, virtually clean air
passing through HEPA filters 48 is exhausted out baffled exhaust
ports (not shown) having doors (not shown).
This description is provided for illustration and explanation. It
will be apparent to those skilled in the relevant art that
modifications and changes may be made to the invention as described
above without departing from its scope and spirit.
* * * * *